The present invention relates to mobile radio networks and more specifically to methods and systems for allocating parameters at an interface to their respective transmission channels.
According to a prior network standard known under the designation GSM, a radio frequency is occupied by a subscriber, and only allocated to this subscriber. This frequency is occupied by the subscriber as long as communication is maintained regardless of speaking pauses which may occur, and independently of the performances and services purchased by the subscriber from an associated provider. Since radio frequencies are a resource, which is scarce and not readily reproducible, this state has been deemed to be capable of improvement. After this system of so-called second generation, a system of 2.5th generation followed, the so-called GPRS, as a representative of the third generation, the EDGE network follows. Through the two last-mentioned generations, a multiple number of subscribers are serviceable compared to the GSM network. The available channels are more efficiently distributed, for example, with low speech activity, a lower capacity is required. Moreover, the capacity can be varied depending on the purchased performances and services.
For describing the problematic nature of prior solutions, first, reference is made to FIG. 1. FIG. 1 first shows five nodes of a mobile radio network, namely the GGSN (Gateway GPRS Support Node), SGSN (Serving GPRS Support Node), BSC (Base Station Controller), BTS (Base Transceiver Station) and MS (Mobile System). Between these nodes, various interfaces are disposed: between the MS and the BTS, the Um interface, between the BTS and the BSC, the Abis interface, between the BSC and the SGSN, the Gb interface, between the SGSN and the GGSN, the Gn interface, and between the GGSN and the MSC (not shown), the Gi interface. The nodes and interfaces between the MS and the SGSN are referred to as GERAN (GSM EDGE Radio Access Network), both for mobile radio networks with GSM, GPRS and EDGE technology. BSC, Abis interface and BTS are combined in a BSS (Base Station Sub-System), wherein a BSC is able to service a plurality of BTS. So-called BSS are sold as a unit by manufacturers, whereby the Abis interface is formed proprietarily according specific manufacturers' definition rather than standardized. In contrast to this, the Um and the Gb interface are standardized. Within a BSS, usually the respective BTS are designed to be cost-effective by providing only limited processing capacity. It is located in the respective BSC. Monitoring the Abis interface is desirable since many parameters relevant to the air interface (Um) are transmitted there. Monitoring these parameters is not possible at the Gb interface since they are no longer present there. With respect to FIG. 1, for example, this is the case for the parameter PCU (Packet Control Unit), which is used for transmitting useful data. In practice, the physical connection between a BTS and a BSC is realized by multiple PCM (Pulse Code Modulation) connections, especially 1 to 4 E1/DS1 lines. Each one of these lines is composed of 32 (E1) or 24 (DS1) channels. Each transmission channel transmits data with a rate of 64 kbits/s. The channels can be divided into sub-channels with data rates of 8 kbits/s, 16 kbits/s or 32 kbits/s.
A transmission channel between BTS and BSC serves for transmitting control plane data. The position of this transmission channel has to be known for monitoring. For determining the position of this transmission channel, for example, the method can find application, that the applicant of the present application has described in the patent application with the publication number 20050030903 entitled “Determining a transmission parameter in a transmission system”, the content of which is incorporated herein by reference. Control plane data is transmitted for establishing and terminating, i.e., for activating and deactivating, a user plane connection (speech or data) on the transmission channel for control plane data, which contains information about the transmission channel for user plane data. As already mentioned, this information relating to the user plane connection may be specific to each manufacturer. Some manufacturers for example use indices to specify transmission channels for user plane data. Others explicitly specify the transmission channel, the transmission sub-channel and the bandwidth. The correlation between these parameters on the one hand and the transmission channels for a user plane connection on the other hand may be stored within the BSC as an allocation table. For example, the allocation table may be transmitted by the BSC to a BTS only once, during initialization phase of the BTS.
For monitoring or analyzing user plane connections, a protocol monitor connected to all of the physical connections between BSC and BTS, requires the correlation information which may be contained in the allocation table. Since, normally, it is impossible, difficult, or otherwise undesirable to perform a reset at the BTS to initiate the retransmission of the content of the allocation table, the previous solution is to manually transmit the content of the allocation table to the protocol monitor.
FIG. 2 shows the just described correlation, according to which control plane data (control plane) and user plane data (user plane) are transmitted over at least one physical connection. The control plane data especially includes data for establishing a connection for transmitting user plane data as well as for controlling the data transmission. The data transmitted on the user plane can especially be circuit switched speech or packet switched data according to the GPRS and EDGE standard. In block 10, the control plane data is evaluated to determine at least one parameter allocated to at least one transmission channel. With this parameter, information is found, for example, by means of the allocation table 12, which allows the protocol monitor to open at least one transmission channel, on which user plane data is transmitted, see block 14. However, the approach known from the prior art, suffers from the disadvantage that for manual transmission of the allocation table to the protocol monitor, expert knowledge is required, which typically is not available to a technician installing a protocol monitor. The experts currently entrusted with this task are highly qualified experts and therefore, their operation is associated with high cost.